Method and device for applying rubber coatings to fabric bands



Feb. 24, 1953 w. ST-EGEMANN 2,629,424

METHOD AND DEVICE FOR APPLYING RUBBER COATINGS 'lO FABRIC BANDS Filed Sept. 25, 1950 Patented Feb. 24, 1953 2,629,424

UNITED STATES PATENT OFFICE METHOD AND DEVICE FOR APPLYING RUB- BER COATINGS TO FABRIC BANDS Walter Stegemann, Hamburg-Harburg, Germany,

assignor to Phoenix-Gummiwerke A. G., Hamburg-Harburg, Germany Application September 25, 1950, Serial No. 186,508

2 Claims. 1 The invention relates to a method of treating fabrics and constitutes a continuationin-part of my patent application, Serial No. 77,436, filed February 19, 1949, now abandoned.

2 or its construction elements will permit a rubber layer to adhere thereto. the invention is that when employing the method of spraying the Desmodur solution onto the fab- More particularly, the invention relates to a ric, it is possible to operate with a substantially method to prepare fabrics or fabric threads for shorter period of drying before the rubber layers uniting the same with a rubber coating. are applied to the fabric.

It is an object of the invention to treat such In the accompanying drawing is illustrated by fabrics and threads which are employed in the way of example a device for producing rubber manufacture of conveyor belts which consist of conveyor bands in accordance with the method of rubber provided with an insert of fabric and are the present invention. made by applying a rubber coating to one side or Fig. 1 illustrates diagrammatically a side eleboth sides of a fabric band. vation view of the device and For the purpose of making fabrics adherable Fig. 2 illu diagrammatically a top p to rubber, it has been proposed heretofore to view of the device. move the fabrics or the like through a bath con- Referring to the drawing, a fabric band l such sisting of aDesmodur solution, whereby this soluas cotton duck or other material adap for tion penetrates deeply into the interior of the forming an insert in a conveyor band covered fabric band. Fabric bands saturated in this i with rubber is unreel d from a pp y pool 2 and manner, however, have to be dried to a certain is passed through a drying chamber 3 where it is extent before the rubber layers are applied to condu ted over a p u y f rs 4 b f re them. The purpose of this drying operation is leaving the chamber 3 through an aperture 5 in to recover from the solution the valuable solvents the top wall of the chamber 3. The aperture 5 such as benzine, gasoline and the like. This reis in communication with a spray chamber 5 covery method, however, requires the employwherein the fabric l is first subjected to a spray ment of expensive devices. of a pair of spraying devices I and 8 before leav- It is now an important object of the present ing the upper end of the chamber 6 through an invention to avoid the employment of expensive aperture II]. The fabric band I is then conducted devices for recovering the mentioned solvents. over a roller H horizontally outside the Spray According to the present invention the Desmodur chamber 6 to a roller [2 and then is passed ownsolution is applied to the fabric band by means of wardly through another ap e i3 back into vaporizing or spraying the solution onto the same. the p y Chamber 6 wherein now e other side The fine distribution of the solution over the surof the fabric band is sp y d with the solution faces of the fabric has the advantage that only by anOtheI' p f p y vi es 14 and t5. very small amounts of the solution are required e fabric band has now been treated on both to obtain a sufiicient preparation of the fabric Sides h the s lution a d. i passed dOWnWardlY band to make the latter receptive for receiving rough an aperture l6 into a chamber I1 for thereon arubber coating and insuring a good ad- Supplying a rubber lay to each side of the herence of the rubber coating to the fabric band. fabric y r.

11-, has been discovered th when applying th The fabric band I is first conducted over tensolution to the fabrics in a very fine distribution sioning rollers l8 and I9 and then passes as just mentioned, the fabric band is sufficiently through an aperture 20 into a heating chamber treated on the outer layers in order to obtain the 5 together With ru yers 2| and 22 app d desired result that rubber layers will readily and respectively to both des of said fabric band. permanently adhere thereto. It is not necessary 5 The rubber layers 2| and 22 are taken from' upfor the solution to penetrate entirely through the p y $130015 23 and 24 respectively, ged in the body of the fabric. In fact, such a. complete Chamber In the drying chamber 25, in penetration may under certain circumstances rewhloh a temperature of about 135 C. is mainsult in undesirable technological changes in t tamed the united layers 1, 2| and 22 are conmaterial of the fabric. The desired materials for ducted over a plurality of rollers 29 and the improving the adherence of rubber to fabric finlshed co veyor band leaves the device through layers, even though they consist of solid materials, the discharge aperture 30.

may be readily converted by a suitable solvent The spray devices I, 8 and l4, l5 of which tw into the form of a highly concentrated solution pairs are arranged in the spray chamber 6 conwhich when vaporized or s rayed upon the fabric sist each of an air nozzle 7 and M respectively Another advantage of and a Desmodur nozzle 8 and I respectively. The nozzles 1 and 14 are supplied with compressed air by an air supply pipe 32, while the Desmodur nozzles 8 and I5 are connected by a pipe line 33 with a tank 34 containing the solution to be applied to the fabric band. The compressed air jet issuing from the nozzles 1 and [4 causes the Desmodur solution to be drawn upwardly in the pipe 33 to be conveyed by the compressed air in finely distributed condition onto the fabric band.

Referring now particularly to Fig. 2, it will be noted that the spray chamber 6 is provided at both ends with laterally extending conduits 36 and 31 both of which are connected to a duct 39 in which is arranged a fan 40 for creating a draft in the direction of the arrows 4|, so that the air is continuously kept in circulation through the spray chamber 6.

The tank 34 may contain, for instance a solution consisting of 20% Desmodur in methylene chloride. Desmodurs are biand poly-functional isocyanates which are used to advantage in adhesives and have been proven very useful in treating fabric bands of the type used in accordance with the present invention. The conversion of this solution into a fine spray takes place in the spray chamber 6 at room temperature (approximately 20 0.). The composing of the band I, 2| and 22 in the heating chamber takes place at an elevated temperature of about 135. C., as already mentioned previously. The application of the rubber layers 2| and 22 to the fabric band I can take place immediately after the fabric has passed through the aperture IS without prior drying, because the fabric band has taken up only sufficient solution as is required for a good and permanent adherence of the rubber layers 2| and 22.

What I claim is 1. In a device for manufacturing a rubber coated fabric band, an elongated spray chamber, means for continuously moving said fabric band through said spray chamber, means including spray nozzles in said spray chamber for applying a fine spray of an adherence promoting liquid to the surface of said moving fabric band, said spray nozzles issuing their spray all in one direction lengthwise of said spray chamber, a duct connecting both ends of said spray chamber with each other, a fan in said duct for circulating air through said duct and said spray chamber in the direction in which the sprays are discharged from said nozzles, two supply spools for rubber layers arranged outside said spray chamber adjacent the point where the treated fabric band leaves the same, means for conducting the rubber layer in engagement with opposite sides of said treated fabric band, and means for pressing said rubber layers during the continuous movement of the fabric band in intimate contact with the latter to form a composite structure.

2. In a device for manufacturing a rubber coated fabric band, an elongated spray chamber, means for continuously moving said fabric hand through said spray chamber, means including spray nozzles in said spray chamber for applying a fine spray of an adherence promoting liquid to both sides of said moving fabric band, said spray nozzles issuing their spray all in one direction lengthwise of said spray chamber, a duct connecting both ends ofsaid spray chamber with each other, a fan in said duct for circulating air through said duct and said spray chamber in the direction in which the sprays are discharged from said nozzles, two supply spools for rubber layers arranged outside said spray chamber adjacent the point where the treated fabric band leaves the same, mean for conducting the rubberlayers simultaneously in engagement with opposite sides of said treated fabric band, and means for simultaneously pressing both said rubber layers during the continuous movement of the fabric band in intimate contact with the latter to form a composite structure.

WALTER STEGEMANN REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Polyisocyanates in Bonding, by T. J. Meyrick and T. J. Watts, from Transactions Institute Rubber Industry, page 156 (Cord Fabric), vol. 

